You've probably heard of Intagram, the app that lets you apply a wide gamut of filters to your photographs as you take them or after the fact and then share the glorious results with your mates.

What you probably haven't heard of though is the Holga SLFT-IP4, an iPhone case that comes with a cassette of filters that you rotate into position and snap away to create an array of different effects.

Taking the retro vibe to the extreme, you don't need to install any dedicated apps but merely choose the right filter that suits your mood.

Once fitted you have access to nine different and crazy special effects and filters without any software or app installed. According to Holga the case is designed to look like an old-school telephone, allowing you to dial in your preferred special effect.

- Yellow Filter with Clear Centre: Clear circular spot in centre to stand out with surroundings in pale yellow to mimic sunset

- Blue Filter with Clear Centre: Clear circular spot in centre to stand out with surroundings in blue to mimic gentle moon atmosphere

Our favourite has to be the heart shaped filter that adds a clear heart in the centre of a red-filled image, be it your favourite chocolate or your best friend. Sadly in our case it was Matt Warman, technology writer at The Telegraph who, unluckily for him, happened to be standing by us at the time we slipped the Holga case over our iPhone 4S.

If you fancy having a play, or actually rather fancy getting one for your iPhone 4 or iPhone 4S, you should zip down to the Conran Shop on the Fulham Palace Road in London.

This Holga SLFT-IP4 case is available in a choice of Red, Blue, White, Black or Silver. It costs £25.